I started on meds a day ago for back shingles. i have 2.5% lidocaine & 2.5% prilocaine in a lotion. can i use this on my sores/ rash on my back for pain relief? if so do i apply it directly on the rash sores?

Some lidocaine patches have been FDA approved for shingles pain . They are worn for only 8-12 hours to prevent toxicity of Lidocaine which can have cardiac effects, would not use for more than 12 hours/ day total and only 2 patches maximum. Since lidocaine lotions are not approved I cannot comment on them. Follow up with MD https://medlineplus.gov/druginfo/meds/a603026.html